As a type of bearing that is simple and superior in quietness and economic efficiency, a sintered bearing has conventionally been used in various motors of, for example, automobiles and household electrical appliances. However, in recent years, due to the improved performances or downsizing of the motors, it is required that a sintered bearing possess a higher wear resistance and durability than those of the conventional ones, which is particularly noticeable in the case of electric motors for automobiles.